EcoSolar Reaches for the Sky at SKYCITY
Visitors to Auckland’s most prominent landmark now have something new to look at alongside the fabulous views over the city. SKYCITY has just installed a large solar water heating system on the roof of its hotel, to help cut energy use and greenhouse gas emissions. Visitors to the Sky Tower are able to see the installation from the tower, and also watch a short explanatory video about how the solar water heating system works, alongside real time monitoring of how well the system is performing.
SKYCITY hopes the prominent installation will inspire other businesses and households to look at efficient water heating, as well as prove to be a sensible investment that will cut costs in the complex over the long term. The project was supported through the EECA Innovation Fund which supported the uptake of solar water heating, including commercial-sized solar water heating installations that could be replicated by other businesses. EECA provided $70,000 of funding towards the project, which made up around half of the total project cost.
The installation comprises 22 solar collectors totalling 61 square metres located on the roof of the SKYCITY Hotel. Operating as a drainback system, the water is circulated through the collectors and preheats the cold water prior to it entering the hot water calorifiers located in the basement carpark level. The hot water flow rate was data logged which showed that there was always a demand for hot water, which could peak at around 13 litres per second. Given that there is always a hot water demand and the high quantity of cold water is able to absorb all the heat from the proposed solar water heating system, a unique solar preheat system was designed by Ian Sumner of Energy Conscious Design and EcoSolar. Instead of the solar system heating water within storage cylinders, on its way to the existing calorifiers the cold water passes through a flat plate heat exchanger where it is preheated by the solar water heating system. This design will maximise the system efficiency. The solar system operates as a drainback system and is therefore inherently failsafe and reliable, easily overcoming risks or reductions in performance associated with frosts or overheating.
With the cold water preheated prior to it entering the calorifiers, the solar system is expected to save around $17,000 a year in gas bills and significantly reduce greenhouse gas emissions.
The solar system is monitored and data logged by Energy Conscious Design’s new “Solar Monitor”, this web-based system monitoring, evaluation and reporting tool shows realtime the actual system operation in full animation, with updates every 10 seconds. The “Solar Monitor” is unique, as far as we know, unique in the World, with several high proFile installations currently being installed. The “Solar Monitor” is free and is proving to be a very useful commissioning and evaluation tool. As well as allowing access to the realtime animation, the “Solar Monitor” records all measured values and allows access to this historical information. The next proposed update to the “ Solar Monitor” will allow the historical information to be analysed against how the system should be operating and automatically report system operation, performance and any notifications. To visit the SKYCITY monitoring and data logging click here. The Solar Monitor animation will be shown together with video as an educational and promotional tool on a 32 inch screen being installed on the Sky Tower.
Jon Woodbridge-Buys, SKYCITY’s Energy & Environment engineer who managed the project, says “the pre-heating design was the most efficient use that could be made of solar heating for SKYCITY’s particular use. The large kitchens in the Hotel and Casino generate a hot water demand proFile that was a very good match for the proposed solar system, and we did not require large storage tanks for hot water with EcoSolar’s innovative design. It is an elegantly simple design.”